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Found leak in copper pipe under concrete!

Discussion in 'Plumbing and Central Heating' started by blueharvester, 20 Oct 2010.

  1. blueharvester

    blueharvester

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    I've found a leak in the central heating system pipes that are buried under the concrete in our kitchen. It seems that the T-junction is where the problem is, see red circle in the photo here. The two smaller pipes that are coming off the bigger pipes were installed after the heating system was put in - they are used to supply the radiator in the sunroom.

    The plumber is coming out on Friday to fix the leak, and I am assuming he will replace the joint and use solder. My question is - how strong is a solder joint and is it the strongest type of joint for copper pipes?
     
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  3. seco services

    seco services

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    solder will hold for yrs better than a compression joint etc
    compression should only be fitted where accessable.

    the joint has more likely failed/corroded due to it only being protected by hairfelt lagging.
     
  4. blueharvester

    blueharvester

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    So, should the joint be easy enough to fix? And, once fixed, should I wrap the joint as well as the remaining joints in some insulating tape before replacing the foam insulation?
     
  5. seco services

    seco services

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    denso tape.
     
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  6. Richard C

    Richard C

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    A cautionary tale; I had to reroute 22mm feed & return pipes on my own heating system in order to install a new soil stack. Pipes were in a floor duct filled with vermiculite & heavily tarnished much like yours. Old pipes cut, thoroughly cleaned (or so I thought) new rerouted pipe work & fittings cleaned & all soldered into place. The system ran for a month OK with the floor trench open & was then back filled, re-screeded & new hard wood floor laid over part of it. Two months later I noticed steam rising from the hole in the floor where the new stack was (it hadn’t been backfilled or boxed in yet); obvious something had gone wrong & I was forced to open it all up again. One of the new solder fittings had failed where it connected the old pipe & there is now a compression joint under there!

    Normally I would always agree solder fittings are best but make sure access around the pipe will allow you to thoroughly clean the old pipe work, that you can check to see it’s thoroughly clean & that no moisture inside the pipe to contaminate inside the joint; my solder ring looked fine but the bond obviously wasn’t. :evil:

    Use Denso tape as sugested.
     
  7. blueharvester

    blueharvester

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    How should I check that the plumber will do this without seeming interfering or trying to tell him how to do his job?
     
  8. Paul Barker

    Paul Barker

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    We know when we have made a good joint, and we know when we may be in trouble, we wouldn't leave a fitting which we were conscerned about until we were no longer conscerned.

    If he can't discern that he is no good anyway. Nothing you can say will help him be a good plumber. you either have a good one or you don't. you will find out by results.
     
  9. blueharvester

    blueharvester

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    Yeah, I guess you're right. So I guess in order to test that the joint is working correctly I should leave the hole open for a month or two and keep an eye for leaks, right?
     
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  11. Richard C

    Richard C

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    It stands to reason that even a half intelligent plumber will want to ensure the joints are cleaned & prepped properly, no one would want to dig a floor up again. I’m not a trained plumber but do have considerable experience on heating systems & general plumbing work, mainly bath/shower room refurbs these days. I may have just been unlucky, I can count the number of bad joints I’ve had on one hand & I still got caught out; not initially either!

    I thought you were doing the repair yourself & my point was to take extra care but I would now think twice about solder fittings on corroded or heavily tarnished pipe if I couldn’t guarantee knowing it was 100% clean.
     
  12. Paul Barker

    Paul Barker

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    Yes or just break up floor again later if necessary. If we have made a good joint we don't get called back. but it is a skill you have to develop you can't dictate it, the person either has it or doesn't.

    People watch me most of the time and I appear to do it with ease, but I say to them it looks easy but it isn't, there is a lot going on in my head and I am thinking all the time while I am working. I can't stand being talked to while I am working as I have to stop, wait until they finish and then get back to my thinking and working.
     
  13. blueharvester

    blueharvester

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    This is all really good advice fellas, thank you. The plumber has done work for me before and he seems to know his stuff, so hopefully it'll be grand.

    I'll probably not be re-tiling for a few months anyway at the very least, so if needs be I can dig up the hole again.
     
  14. Nige F

    Nige F

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    You`re still wiping joints then :LOL: . Skill, schmill
     
  15. doitall

    doitall

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    The main problem will be getting the water out and the pipe dry.
     
  16. blueharvester

    blueharvester

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    I'm gonna leave the hole exposed and lift the tiles, then hire a de-humidifier, will this do the job?
     
  17. Richard C

    Richard C

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    Think doitall means getting the residual water from the C/H pipe & getting it dry before attempting to solder; its the same thing I was referring to.
     
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